Objective: To investigate the relationship between the polymorphism of tumor necrosis factor-alpha gene--308G/A and premature births.
Methods: DNA was extracted from the blood samples taken from 96 women using chelex-100 method, among whom 46 gave premature births and 50 gave normal births. Then PCR-RFLP was performed to determine the TNF-alpha-308 gene polymorphism.
Results: (1) The frequencies of TNF-alpha -308 genotype TNF1/1 (GG) and TNF1/2 + TNF2/2 (GA + AA) were 60.9% and 32.6% +/- 6.5% for the women given premature births and 82.0% and 12.0% + 6.0% for the women given normal births, respectively. The allele frequencies of TNF1(G) and TNF2(A) were 77.2% and 22.8% for the women given premature births and 88.0% and 12.0% for the women given normal births, respectively. The differences were statistically significant (P < 0.05). (2) The women with genotype TNF1/2(GA) and TNF2/2(AA) were 2.929 (95% CI 1.152-7.447) times of those with TNF1/1(GG) in risk of giving premature births. The women with allele (TNF2) were also more likely to give premature births, with an odds ratio (OR) of 2.169 (95% CI 0.999, 4.709) compared to those with TNF1.
Conclusion: Gene polymorphism of Tumor Necrosis Factor-alpha promoter region in--308 site is associated with increased risk of premature births. TNF2(A) allele may be a risk factor of premature births in Chinese populations.